A worker is in a critical condition after being pulled from a lake on the Queen's Sandringham estate.
Reports suggest that an estate worker, believed to be in his 30s, was operating a ride-on lawn mower when he fell into the lower lake yesterday.
Emergency services were called to the Norfolk retreat at around 1.30pm.
A spokesman for Norfolk Police said: "The man was retrieved from the water and was taken to Addenbrooke's Hospital by air ambulance for treatment. He is currently described as being in a critical condition."
Two men have been arrested on suspicion of murdering a teenager whose body was found on the Queen's Sandringham estate.
Norfolk Police said they had made the arrest earlier today in connection with human remains, identified as those of missing Latvian 17-year-old Alisa Dmitrijeva, which were found on the estate in Norfolk on January 1.
The men, aged 28 and 31 and from the Wisbech area, are being questioned at a police station in King's Lynn.